Question

Raghu wants to make a closed aluminium cone for his science project. The slant height and radius of the cone are 10 cm and 7 cm respectively. Find the area of aluminium sheet required to make the cone.(Use $\pi =\frac{22}{7}$)

• A. $400{cm}^2$
• B. $267{cm}^2$
• C. $258{cm}^2$
• D. $374{cm}^2$

Answer 1

The correct option is D

$374{cm}^2$

Given,
Radius of the cone, $r=7cm$
Slant height of the cone, $l=10cm$

Area of the aluminium sheet required to make the cone = Total surface area of the cone $=\pi r(l+r)$
$=\frac{22}{7}\times 7\times (10+7)$
$=22\times 17$
$=374{cm}^2$